Work in our laboratory with embryonic kidneys and lungs in organ culture has demonstrated that hyperoxic atmospheric conditions markedly inhibit normal organogenesis. In addition, adrenocorticosteroids have a similar effect on the morphology of development in this experimental model. An investigation into the chemical nature of cell surface- associated substances during early morphogenesis of embryonic kidneys and lungs will be undertaken. The effects of adrenocorticosteroids and of varying concentrations of atmospheric oxygen will be studied. Progressive changes in morphologic development of organs will be compared with histochemical characteristics of the saccharide components of membranes using such techniques as differential lectin affinity studies, C14-D-glucosamine uptake into glycosaminoglycan material of the surface membrane as determined by radioautography and histochemical identification of surface mucopolysaccharides and compared with parameters of general metabolic function such as oxygen consumption, glucose metabolism and formation of RNA, DNA and protein. Modification of cell surface characteristics by addition of varying quantities of plant lectins and of cytochalasin B will be studied in order to characterize phenomena of organogenesis as related to epithelial membrane chemistry. The role of microtubules in nephron and lung formation will be assessed by the addition of colihicine or vinblastin to the organ culture system. This work will provide a fundamental basis for observations made in experimental models of organ development analogous to similar events seen in the malformed organs of the human neonate.